Similar to trends both globally and in the United States, the burden of obesity and diabetes in New York City (NYC) is projected to increase - possibly to overwhelming proportions. Our large primary care health system on the West Side of Manhattan (St. Luke's Roosevelt Hospital Center) has been delivering primary care to a large population, a large proportion of which are minorities at high risk for type 2 diabetes. We have assembled a strong research team including diabetes and obesity clinical research leaders, clinicians with strong community service record and lead public health epidemiologists in New York City. A uniform electronic medical records system (EMR) is being implemented in the next 2 years, in phases, into our primary care practices. The same EMR has been implemented in adjacent health systems on the West Side, federally- funded community health centers (Ryan Clinics) New York City Department of Health Primary Care Initiative - sponsored private practices. This presents the opportunity to form a clinical network where well worked out changes in health policy and care design could easily be implemented and tested. We are completing development of a standard diabetes management system (SDMS) that is in accordance with current practice for diabetes prevention and care, and can be added to the EMR. This will contain the use of a screening questionnaire for detecting individuals at risk to develop type 2 diabetes and a prompt to order an A1C test in those identified to be at risk. We are also working on development of an enhanced management and education for diabetes system (EMEDS) that incorporates all components of the Chronic Care Model and the latest evidence based recommendation for care with regard to diabetes prevention and management. We will be able to implement EMEDS in our practices, one site at a time. We will take advantage of the delayed implementation schedule to evaluate the effectiveness of our systems in a modified natural experiment design. We will conduct retrospective analysis on data collected throughout the natural experiment. The Primary Aim is to examine whether implementation of EMEDS across a network of primary care practices will result in greater reductions in A1C than the standard care, over a 12 month follow-up period of patients with pre-diabetes (A1C 5.7-6.4%) or new diabetes (A1C >6.5%) diagnosed through our screening system. We hypothesize that the average A1C level of patients exposed to sites/providers that implement EMEDS will be lower than that of patients exposed to SDMS at 12 months. Data will be collected from the EMR which would have been set up at all practices before the study started. This experiment will occur at multiple levels in our health system and will involve a change in the health policy for the entire system and a change in the entire health system as the entire population will be asked to undergo screening at the point-of-care. Moreover this experiment will generate methods and tools that will be easily leveraged to other health care systems.